Things got rather testy during a discussion on HBO's "Real Time with Bill Maher" Friday, after journalist Glenn Greenwald erupted at Iraq and Afghanistan Veterans of America founder Paul Rieckhoff while talking about Edward Snowden.

"I think everybody across the political spectrum would agree, the problem is way too much secrecy, and not enough transparency," Greenwald said during the panel, on the topic of government secrets and fugitive ex-NSA contractor Edward Snowden.

Maher brought up Richard Clarke, former counterterrorism czar and member of a five-person panel to look into the NSA following the Snowden leaks, who called what he did "treason" back in December. But it was Rieckhoff's words that got Greenwald fired up.

"There’s a larger debate here if Snowden did release these documents and we find out it does perform a service, at the same time he’s still hiding in Russia. I mean, it would be a different story if he came back, and made his case, and faced the music,” Rieckhoff said.

"That is total bullsh----," Greenwald said to audience applause. "Let me just say this. Why would Edward Snowden want to come back to the United States, a country that has a systematic attack on whistleblowers?"

Both talked over each other, as Rieckhoff said Snowden was "hiding" in Russia, to which Greenwald said he "has asylum."

The shouting match continued. Later, after Maher read quotes from Richard Clarke, who said Snowden's leaks "helped the terrorists and people like Putin," the exchange heated up, as Greenwald pointed out that governments have always said things like that about whistleblowers of the past.

"You have such certainty, how do you know that the information he revealed did not cost American lives?" Rieckhoff asked.

"What American lives? Is there a single piece of evidence?" Greenwald said. "This is propaganda. Where are the dead Americans?"

Maher later made the point that any deaths would remain secret, however, saying, "If they were in the CIA we wouldn't know their names, there would just be a star on the wall."